Research On The Strength And Durability Of The Heavy Duty Asphalt Pavement Of Graded Road

With the sustained growth of the national economy, the highway career of our country has developed fast, but the traffic of main road increases day by day and the overload proportion is very high, all of them have caused a large number of early damage of the asphalt pavement, and this damage phenomenon is very serious to the main road. Therefore, to carry out the research of main road Heavy-duty Asphalt pavement durability has important practical significance.This paper selects the typical pavement structure form of Henan provincial trunk highway, using ABAQUS finite element software to establish a corresponding mechanical calculation model, and this article analyses the mechanics reaction of the asphalt pavement structure under standard load and overload conditions. Using Bisar software, this article calculates the impact that the structure layer thickness and Sub-grade treatment have on road comprehensive property.Firstly, for the typical asphalt pavement structure, under the action of the standard load, the whole asphalt covering is in the state of compression. The shear stress in the wheel load is smaller while it increases sharply in the rim parts and it reaches to the maximum, at the depth of six to eight centimeter range. The stress-strain in the base layer is smaller and in the sub-base layer the tensile stress increases larger, it is close to the allowed tensile stress of the lime stabilized gravel.Secondly, through the investigation and analysis of the overload situation, this article takes the single shaft300kN to conduct the pavement mechanical checking calculation. The calculation results show that, to the typical asphalt pavement, the deformation properties of each structural layer is almost in agreement to that of the standard load situation, but the sub-base bottom tensile stress exceeds the material splitting strength, and the overloading is the dominating factor of the pavement structure, impacting the normal life of the road.Thirdly, for the typical asphalt, this paper using BISAR software to calculated the impact that the changing factors such as the base layer thickness, the sub-base thickness etc. have on the pavement comprehensive performance. The calculation results show that, with the increasing thickness of the base and the sub-base, the fatigue life of the road has been greatly improved. Therefore, increasing the thickness of the base layer and the sub-base layer to improve the fatigue life of the road is economical and feasible. Through the analysis of the3percent and5percent lime soil treatment and the gravel sub-grade treatment, we concluded that the Sub-grade treatment can get an ideal result and all kinds of sub-grade treatment process can considerably improve the lifetime of the road life. In the area affected dramatically by water, we can choose the gravel treatment or use the gravel and lime united treatment method.According to the practical situation of the main road heavy-duty transportation in Ping Dingshan city, through the above comparative analysis we sum up three typical asphalt pavement structures. The computed results indicate that the fatigue lifetime of the three pavement structure all meet the design requirements of the heavy-duty traffic asphalt road.